Sharpness

If you take a close look on magnified pictures taken with
different sharpness settings, you'll find a probability that default sharpness
setting in camera is 'soft'. This could be true. The big problem of camera's CCD
is low resolution ability which brings out dim pictures. The original RAW file is recalculated
so final sharpness depends a little on quality of interpolating
program. Thus, the basic level of sharpness is already set in camera before the
image data is recorded onto disk. This could be found when you compare real
resolution charts of different cameras with same resolution source, when the
tests shows different final resolution results.

The sharpening process uses different algorithms. When the
picture is sharpen, some artifacts of sharpening process could become visible:
ghosting, echo, amplified noise, but the most visible consequence of sharpening
is stronger light-dark line on contrast edges. You can find a sharpening
artifacts described on the page of Computer
sharpening.